Book/Report

FZJ-2019-01817

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Untersuchung von Edelgasen und Edelgasmischungen auf Pt(111) und des Systems Al/Au(111) mittels temperaturvariabler Rastertunnelmikroskopie

Hannemann, H. (Corresponding author)FZJ*

1997
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/21827

Report No.: Juel-3351

Abstract: The adsorption ofkrypton, xenon and Krl-xXex-mixtures on Pt(111) and the system Al/Au(111) were studied with temperaturevariable scanning-tunneling-microscopy(STM). It is possible to detect the unoccupied xenon 6s- and 6p5d-states with STM via measuring the imaged height of the xenon islands as a function of bias. At negative tip bias upto U$_{T} \geq$ -5.5V the xenon islands are imaged with a constant height of 2.26$\mathring{A}$. With changing the bias to -5.5V $\geq$ U$_{T}$ $\geq$ -9V strong variations in the imaged height appear, that show a clear correlation on the xenon unoccupied state-levels. The results are explained in terms of resonant tunneling. The investigation of the monolayer krypton reveal beside the from TEAS-measurements well-known hexagonal R30° - and R0° -phase surprisingly a quadratic phase, which is interpreted to be an intermediar phase between the two hexagonal phases. Kr$_{1-x}$ Xe$_{x}$-mixtures adsorbed on Pt(111) were investigated as a function of molarfraction $\chi$ and sample-temperature T. After successive adsorption of the components at T = 17K krypton and xenon are separated because the mixing is kinetically hindered. Following annaeling to T = 27K leads to a mixing of the components. The mixing process is performed by a diffusion of xenon into krypton and not vice versa. At T = 36K a complete mixture is reached, which corresponds to a structure with small xe-rich and kr-rich islands. Further annaeling only leads to an increasing island size. The deposition of aluminum on Au(111) leads to a surfacealloy by replacing goldatoms by aluminum-atoms. Therefore, after aluminum-deposition gold-islands grow on the surface. The surprising solubility of aluminum in gold is attributed to the possibility of aluminum to reduce the surface stress of the Au(111)-surface because of its high electron-density. The incorporation of aluminum atoms into the Au(111)-surface involves a change and finally the disappearance of the Au(111)reconstruction. When the maximal solubility of the aluminum-atoms is reached, pure aluminum-islands start to grow.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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